British Foreign Secretary William Hague said he deplored the fact that North Korea "has chosen to prioritize this launch over improving the livelihood of its people."
The North's failed launch in April ended a deal for the United States to provide thousands of tons of food aid to the country.
In his father's footsteps
"I think this is very important to Kim Jong Un to build political legitimacy and bolster the spirits of his people," said James Schoff, a North Korea specialist with the Carnegie Endowment for International Peace. "He is doing this despite the fact that he knows he is going to come into a lot of criticism in the region for it."
The launch has taken place during a period of power consolidation for Kim in which he has purged senior military officers in an apparent effort to stamp his authority on the regime's leadership.
"If Kim Jong Un pulls off a successful long-range missile test, it's a very important signal saying that 'Yes, I, Kim Jong Un, have replaced the powerful generals,' " said John Park, a Stanton junior faculty fellow at the Massachusetts Institute of Technology. "It shows that 'I have found the right balance and I am now in charge.' "
The launch also ties in with important dates for the regime's ruling dynasty.
Pyongyang had said this rocket launch would be "true to the behests" of Kim Jong Il, the late North Korean leader and father of Kim Jong Un.
Kim Jong Il died on December 17 last year, so the rocket launch took place just days before tearful mourners are expected to gather for the first anniversary of his death.
Experts had also speculated that North Korea wanted this launch to happen before the end of 2012, the year that marks the centenary of the birth of Kim Il Sung, the founder of North Korea and grandfather of Kim Jong Un.
Another factor may also be at play: The launch took place ahead of national elections in Japan on Sunday and in South Korea on December 19. North Korea is a crucial foreign policy issue in both of those countries.
The rocket took off Wednesday morning and flew south over Japan's Okinawa islands. There were conflicting reports about how many parts fell into the sea.
A launch had seemed unlikely to take place so soon after North Korea announced Monday that it was extending the rocket's launch window into late December, citing technical issues with an engine.
Previous attempts by the North in 1998, 2006, 2009 and April of this year failed to achieve their stated goal of putting a satellite into orbit and provoked international condemnation.
The rockets launched in 1998 and 2009 flew for hundreds of kilometers but didn't succeed in deploying satellites, other countries and experts said at the time. North Korea nonetheless insisted that both satellites did reach orbit, with KCNA reporting that they were transmitting "immortal revolutionary" songs back to Earth.
The 2006 launch failed soon after takeoff and wasn't reported by state media.
In April, the North Korean regime invited members of the international news media, including CNN, into the country to observe the preparations for its planned launch. But the strategy backfired when the rocket broke apart shortly after blasting off. On that occasion, state media took the unusual step of admitting the launch's failure.